/**
* returns copy
* @see prototype.js Enumerable#findAll
* @see http://www.imgsrc.co.jp/~kuriyama/prototype/prototype.js.html#Reference.Enumerable
*/
Array.prototype.select = function(func)
{
var ary = [];
for (var i = 0; i < this.length; ++i)
{
if (func(this[i]))
ary[ary.length] = this[i];
}
return ary;
};

function managers(emps)
{
return emps.select(function (e){ return e.isManager; });
}

function highPaid(emps)
{
var threshold = 150;
return emps.select(function (e){ return e.salary > threshold; });
}

function paidMore(amount)
{
return function(e){ return e.salary > amount; };
}

var highPaid = paidMore(150);

var john = new Employee();
john.salary = 200;
document.write(highPaid(john));